The purpose of this project is to evaluate the average and age-specific incidence rates of various chronic pain syndromes, and to investigate the relationship between occurrences of these pain conditions with various epidemiological factors. (1) The incidence rates of disabling and/or severe headache were evaluated with data obtained from a Mid-West non-clinical population survey. The relationship between incidence and prevalence rates and length of illness due to headache has been examined. A report of the results of this study has been prepared. (2) A study is currently being developed to evaluate the average and age-specific incidence rates of neck-back pain and low back pain based on the data from NCHS national surveys. The association of these pain syndromes with various demographic, psychological and medical-care variables will be investigated.